Vehicles typically include low voltage power distribution systems to power a wide variety of vehicle components and accessories. Representative automotive and transportation vehicle applications may include a 12V or 24V low voltage power distribution system, respectively, to power vehicle control modules, such as a powertrain controller, body controller, battery controller, and the like as well as vehicle lighting, HVAC, windows, mirrors, wipers, infotainment system, navigation system, and countless other systems, motors, actuators, sensors, modules, etc. The increasing demands on vehicle power distribution systems are nearing practical limits of the 12V and 24V systems. As such, higher voltage levels, such as 48V for example, have been proposed and discussed in automotive industries for several years. However, various accessories, components, or devices may not be compatible with a new, higher voltage. To address this issue, various automotive OEM and suppliers have suggested a two-voltage or dual voltage distribution system with a high power bi-directional converter to connect the two voltage distribution systems together.
Currently proposed dual voltage distribution systems include a number of design challenges. For example, converters generally operate with high efficiency only within a limited operating range of loads. Proposed systems also employ a second battery that increases cost and complexity of the system and requires additional voltage and current monitoring. These systems would also use additional copper wiring in more complex wiring harnesses to supply each voltage level to loads disposed throughout the vehicle. Flexibility of these systems is also limited for future system upgrades.